Pilot wave generator



Feb. 26, 1946. H. M. STOLLER PILOT WAVE GENERATOR Filed July 7. 1942FIG.

ARMA TURE' WIND/N68 lNl/ENTOR H. M STOLLER A 7'TORNE V Patented F eb.26, 1946 UNITED STATES PATENT OFFICE PILOT WAVE GENERATOR Hugh 3!.Stalks, Mountain Lakes, N. J., assignor toBell This invention relates toapparatus for generating an alternating wave of certain frequency.

and more particularly to an electrical motor for generating a pilot waveof certain frequency such that variations of the frequency of the pilotwave are utilized to control the speed of the motor.

Heretofore, electric motors have been provided with suitable apparatusfor generating a pilot wave whose variations of frequency have beenemployed to control the speed of the motors. One such motor togetherwith a pilot wave speed regulator therefor is disclosed in m Patent1,695,035, granted December 11, 1928. In the prior motors of theaforementioned type, the pilot wave generator was usually disposed atone end of the armature thereby tending to increase the overall axiallength of the motor. Such prior motors were employed where the over-alllength thereof was of no special concern, The present invention isespecially applicable in situations where economy of both space andweight is an important factor, such as in the field of aircraft,

The present invention contemplates a pilot wave generator embodied in anelectrical motor such that both the combined generator and motor effectsubstantially maximum economy of space and weight.

The object of the invention is to provide a combined motor and generatorhaving substantially minimum weight and bulk without materiallyimpairing the usefulness of either the motor or generator.

A motor of well-known structure comprises an armature composed of apluralit of laminations stacked on a suitable axle each of whichlaminations embodies a plurality of radial projections arranged inspoke-like fashion and having curvilinear portions formed integrally onthe outer ends thereof. The alignment of corresponding radialprojections and associated curvilinear portions forms effectively aplurality of radial segments extending axially of the axle for a certaindistance. A pair of stator pole-pieces disposed on diametricallyopposite sides of the armature extend coextensively axially therewith.

In accordance with a specific embodiment of the present invention, theaforementioned armature is arranged such that commencing at one endthereof, the curvilinear portions are cut of! alternate segments for apredetermined axial distance, allowing the curvilinear portions toremain on other alternate segments as initially formed. In addition, oneof the stator pole-pieces is adapted, at the armature end from which thecurvilinear portions are cut away, to embody a further stator pole-pieceonto which is applied a suitable electrical winding. The number ofarmature ments and speed of rotation thereof determine the frequency ofthe alternating wave induced in the winding of the further pole-piece.

The invention will be readily understood from the following descriptionwhen taken together with the accompanying drawing in which:

Fig. 1 is a fragmentary perspective view of an electrical motorembodying a specific embodiment of the invention;

Fig. 2 is a partial elevational view of a stator pole-piece included inPig. 1 and comprising a plurality of stacked laminations modified toembody a certain aspect of the invention;

Figs. 3, 4 and 5 are elevational views of laminations included in thepole-pieces shown in Figs. 1 and 2;

Fig. 6 is an elevational view of laminatlons forming a part of thearmature of Fig. 1;

Fig. 7 is an end view of the lamination shown in Fig. 6; and

Fig. 8 is an elevational view of the armature lamination shown in Fig. 6and modified in accordance with the specific embodiment of the presentinvention illustrated in Fig. 1.

Referring to Fig. 1, an armature 9 comprises an axle ll whose ends aremounted in suitable bearings, not shown, and has stacked thereon aplurality of laminations Ii arranged in a cons ous manner and possessingsubstantially a circular configuration which is fiat on both oppofltesides as shown in Figs. 6 and 7. Certain laminations H are to bemodified in accordance with the invention which is to be hereinafterexplained. Referring to Fig, 6, individual laminations ll embody acentral aperture If for effecting the threading thereof onto the axleII, a hub portion II, a plurality of radial projections I attachedintegrally in spoke-like fashion to the hub portion It, and a pluralityof curvilinear portions II former integrally on the outer ends of theradial projections It, The contiguous stacking of the laminations II onthe axle I0 is such that the alignment of the corresponding individualradial projections I 4 and curvilinear portions [5 constituteeffectively a plurality of discrete radial segments or teeth isextending along a longitudinal axis of the axle III as shown in Flg. 1.Suitable electrical windings are applied to the armature 9 in the slotsbetween the teeth It in the usual manner for the usual purp se.

Disposed on diametrically opposite sides of the armature 9. Fig. 1 is apair of stator pole-pieces i1 and Il. The pole-piece ll comprises apinraiity oi laminations It, Fig. 5, stacked in a contiguous manner andextending substantially coextenslvely with the armature I as shown inPig. 1. The pole-piece I! also extends substantially coextensively withboth the pole-piece II and armature 0, Fig. l, and comprises anunsymmetrical structure in accordance with the invention which will besubsequently explained. It is understood that the pole-pieces I1 and IIembody suitable electrical windings, not shown, for etiecting anenergization thereof in the well-known manner. The foregoing describes,for the purpose of this illustration, substantially a direct currentmotor, although similar types of electrical apparatus embodyingcorresponding elements are also contemplated.

In accordance with the present invention, a few 6 of the stackedlaminations ii at one end of the armature 8, Fig. l, have thecurvilinear portions I cut oil alternate radial projections I4 as shownin Fig. 8. At the one end of the assembled armature 9, this leaves everyother tooth It cut back an axial distance A-B, Fig. l. The radialprojections H embodied in the individual laminations ll, Figs. 6 and 8,comprise an even number so that the teeth It having the cut-backportions occur the same number of times as the teeth .IS without suchcut-back portions.

Referring to Figs. 1 and 2, the left-hand end of the pole-piece l1embodies a predetermined number of contiguously aligned laminations 38shown in Fig. 3 and having two identical and interior legs 3!, 3| ontoeach of which is applied an individual coil 32 comprising a suitablenumber of turns and preferably serially connected. As both the coils 32require a certain amount of space extending axially towards theright-hand end of the pole-piece ll, a predetermined number oflaminations 35 shown in Fig. 4 and having an internal opening 36 aredisposed adjacent the right-hand side of laminations 30 as illustratedin Figs. 1 and 2. Adjacent the right-hand side of the laminations I5 andextending the remainder of the axial length of the pole-piece N, Fig. 1,is a plurality of contiguous laminations is shown in Fig. 5. Thus, thepole-piece I9 comprises successively contiguous pluralities oflaminations 30,

35 and I! as illustrated in Figs. 1 and 2.

In the operation of Fig. 1, the rotation of the armature 9 causes analternating wave to be induced in the windings 32, 32 in the well-knownmanner of an inductor alternator. The frequency of such induced wavedepends on the number of radial teeth or segments it and the speed ofrotation of the armature 9. Obviously, such frequency increases with anincrease of armature speed and decreases with a decrease of armaturespeed. The present invention may be employed to regulate the speed ofthe motor in the manner of the pilot wave generator disclosed in mypatent, supra.

It will be noted that the motor armature windings pass through theetIective pilot generator rotor, left-hand end of armature 9 of Fig. i,so that the latter portion of the armature 8 functions both as a motorand a generator, thereby minimizing the size and weight of the combinedstructure with reference to similar characteristics of the combinedstructure of the pilot wave generator and motor disclosed in my patent,supra.

What is claimed is:

1. In combination in an electrical apparatus for generating analternating wave of certain asoasu frequency, an armature formed with aplurality oi substantially identical segments each of whichextendsinbothradialandaxialdirectionaa curvilinear portion iormed on theouter ends of certain oi said segments and extending over the entireaxial length thereof, a further curvilinear portion iormed on the outerends of others of said segments and extending partially over the axiallength thereof, said further curvilinear portions commencing apredetermined distance from the corresponding ends of said othersegments and extending over the remainder of the axial length or saidother segments, and stator pole-piece means disposed substantiallyopposite to the portions of said other segments constituting saidpredetermined distance.

2. The combination according to claim 1 in which said certain and othersegments comprise successively alternate segments.

3. In combination in an electrical motor comprising a plurality oflaminations each of which is provided with a circular configuration andembodies a hub portion, a plurality or radial projections attachedintegrally to said hub portion. and a plurality of curvilinear portionsformed integrally on the outer ends of said radial projections, saidlaminations being so stacked that corresponding radial projections andcurvilinear portions lie in axial alignment, and a pair of statorpole-piece means disposed on diametrically opposite sides oi. saidarmature; means to generate an alternating wave of certain frequencycomprising, at one end of said armature, a predetermined number of saidlaminations having said curvilinear portions cut oil a pro-selectednumber of said radial projections, and a further stator pole-piece meansmounted in the portion of one of said stator pole-piece means oppositesaid one end of said armature.

4. In combination in an electrical motor comprising a plurality oflaminations each of which is provided with a circular configuration andembodies a hub portion, a plurality oi radial projections attachedintegrally to said hub portion, and a plurality of curvilinear portionsformed integrally on the outer ends oi said radial projections, saidlaminations being so stacked that said radial projections andcurvilinear portions lie in axial alignment, and a pair of statorpole-pieces disposed on diametrically opposite sides of said armatureand extending substantially coextensively therewith; means to generatean alternating wave of certain frequency comprising. at

one end 01 said armature, a certain number of said laminations arrangedcontiguously and having said curvilinear portions attached to certainradial projections and having said curvilinear portions cut of! otherradial projections, a further stator pole-piece embodied in one of saidpair of stator pole-pieces and positioned opposite to said one end ofsaid armature, and an electrical winding applied to said further statorpole-piece.

5. In combination in an electrical motor comprising an armature composedof a plurality of laminations of substantially circular configuration,each of said laminations comprising a hub portion, a plurality of radialprojections attached integrally to said hub portion in spoke-likelashion and a curvilinear portion formed integrally on the outer end ofeach of said radial projections, said laminations being stacked so thatsaid radial projections and curvilinear portions constitutesubstantially a plurality of unitary axial segments arranged inspoke-like fashion, and a pair of stator pole-pieces disposed ondiametrically opposite sides of said armature and extendingsubstantially coextensively therewith;

means to generate an alternating wave of cer-,

tain frequency comprising, at one end 01' said armature, a pro-selectednumber of said laminations arranged contiguously and to which saidcurvilinear portions are attached to corresponding alternate radialprojections and from which said curvilinear portions are cut oi! othercorresponding radial projections, a further stator pole-piece mounted inthe portion a! one of said stator pole-pieces opposite to said one endat said armature, and electrical windings applied to said further statorpole-piece.

6. In an electric motor, a toothed rotor having an even number of teeth,said rotor formed of stacked laminations, pole-pieces for said motor,armature windings in the slots between the rotor teeth, and means togenerate a pilot wave, comprising every other tooth provided with acut-away portion extending from one end of said rotor for a certainaxial distance, and stationary electrical windings provided on an innerface of one of said pole-pieces, opposite said cut-away portions.

HUGH M. STOILER.

